Renin–containing cells in kidney transplants into the anterior eye chamber

Abstract

As a part of experiments aimed at the study of the effects of denervation on the development of the renin—containing juxtaglomerular epithelioid granular cells (JEG-cells), pieces of fetal rat kidneys were transplanted to the anterior eye chamber of adult animals. These allografts survived and organized an organotypic tissue, with the exception that the renin—containing cells significantly increased in number. The implantations were performed on 15 adult female Wistar (Ivanovas GMBH, BRD) or ZUR/Siv (Zuchthygiene, Zurich, Switzerland) rats anesthetized with 0.1 mliter Nembutal and 0.1 muter Ketalar i.p. and pretreated with a drop of 1% Atropin— sulfate on the cornea [1]. The kidney tissue was derived from 17 to 19 day old fetuses, sacrificed in utero by an overdose of Nembutal to the mother. The kidney was removed with heat—sterilized instruments and cut in small pieces in RPMI1640 cell culture medium supplemented with 10% fetal calf serum. The tissue pieces (kidney cortex or medulla alone and cortex and medulla together; approximately 3 x I x 1 mm) were aspirated in the tip of a Pasteur—pipette and inserted on the iris of the host eye through an incision of the cornea. The animals recovered rapidly and did not show any impairment due to the intervention or the implant. After various survival times (14 days to eight months) the rats were anesthetized again and perfused through the left ventricle with Bouin—fixative. The whole eye with the implanted kidney was dissected out, dehydrated, embedded in paraplast and cut with a microtome. Adjacent, 5 jm thick sections through the kidney implant were stained with hematoxylin—eosin (HE) or incubated with antibodies against rat—kidney renin and angiotensin 11. The immunohistochemistry was performed according to the unlabeled antibody method as described earlier [21. Approximately 80% of the implants survived. They were visible by naked eye as white spots on the anterior surface of the red iris of the host animal. The size of the implanted piece of tissue increased only slightly from the original one. In a few cases, the implant adhered to the cornea without provoking particular reactions. In HE-stained sections, the implants displayed morphologies always reminiscent of a normal kidney, but mostly fairly disorganized and immature (Fig. IA, 3). The kidney implant was supplied by vessels of the iris and was Fig. JA. HE-stained longitudinal section through the eye of an adult female rat in which a piece of fetal rat kidney cortex was implanted for /4 days. The implant grew on the iris (IR) and adhered to the cornea (C). The blood vessels to the implant are derived from iris capillaries (arrow). x 76. B. Consecutive section to IA incubated with antisera against rat—kidney renin. A dilated longitudinally cut (arrow) and two cross—cut (arrowheads) blood vessels contain renin—immunoreactive cells in their walls. In the former the immunoreactivity can be followed over an unusually long distance. x 76. C. Enlargement of Fig. I B. The abundant renin immunoreactive cells (arrowheads) belonging to a vessel contacting the glomerulus (G) is overwhelming. x 300.